Automatic oil burner



June 10, 1958 Filed Nov. '23, 1954 2 S heetsSheet i IN VEN TOR.

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ATTORNEY 2,838,242 Patented June 10, 1958 AUTOMATIC OIL BURNER fitanley C. Paterson, Medford, Mass.

Appiieation November 23, 1954, Serial No. 470,595

1 Claim. (Cl. 236-1) This invention relates to an automatic oil burner.

The invention has for an object to provide a novel and improved automatic oil burner of the high pressure atomizing type wherein provision is made for automatically controlling the burner to provide a high fire or a low fire in response to heating requirements.

With this general object in view and such others as may hereinafter appear the invention consists in the automatic oil burner embodying a high and low fire control responsive to heating requirements and in the various structures, arrangements and combinations of parts hereinafter described and particularly defined in the claim at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention:

Fig. l is a side elevation, partly in section, of an oil burner embodying the present invention and more or less diagrammatically illustrating control mechanism for room heating and responsive to variations in the outdoor temperature;

Fig. 2 is a similar view of the control mechanism illustrated in Fig. 1 showing the same as embodied in a water heating system and responsive to opening or closing of a hot water faucet;

Fig. 3 is a side elevation, partly in section, similar to Fig. 1 showing a modified form of control mechanism for room heating responsive to outside temperatures; and

Fig. 4 is a view of the control mechanism illustrated in Fig. 3 adapted for water heating and responsive to opening or closing of a faucet in the water line.

In general the present invention contemplates an oil burner having an automatic high and low fire control which is adapted for use in a pressure jet type oil burner having a combustion head, an annular chamber through which a supply of air is forced and a nozzle for atomizing a supply of fuel delivered thereto from a source of supply. The present automatic control contemplates automatically varying the pressure at the nozzle within predetermined pressure ranges to produce either a high or a low the in response to heating requirements. In accordance with one embodiment of the present invention outside temperature responsive means is arranged to control a solenoid operated valve which is arranged to direct the flow of the fuel to the nozzle either directly thereto at a relatively high pressure when a high fire is required or through a by-pass having a pressure regulating valve for reducing the fuel pressure prior to its passage through the nozzle when a low fire is desired.

Provision is also made for controlling the atomizing air pressure as a further regulation of the fire in accordance with the operation of the fuel pressure control mechanism.

in another modified form of the invention diiferen'tial pressure responsive mechanism maybe incorporated in a domestic water heating system such that the oil burner may be normally operated to provide a low fire when no Water is being used and to automatically provide a high fire whenever a faucet in the water line is opened to withdraw hot water.

In the operation of prior pressure jet burners the fuel is normally supplied at a constant rate and pressure to the atomizing nozzle, usually at a pressure of about pounds per square inch, and as a result a relatively high fire is provided for room heating irrespective of the outside temperature. Furthermore, when provision is made for heating water in the system the normal firing rate of the burner is usually too low to provide enough heat for the domestic hot water system. Prior to the present invention this problem has been solved by firing the system at a greater firing rate to accommodate the water heating system, and as a result economy of operation is sacrificed.

In accordance with the present invention provision is made for operating the burner at a maximum fuel pressure or firing rate ranging from 100 to pounds per square inch when a high fire is required, and at a minimum fuel pressure ranging from 70 to 100 pounds per square inch when a low fire is required.

Referring now to the drawings, the fuel burner assembly, indicated generally at 10, comprises in general an air casing 12 of any usual type and a motor driven fan 14 adapted to deliver air through the casing 12. The forward end of casing 12 is provided with an atomizing spray nozzle 18 to which oil is delivered under pressure. The air casing 12 is further provided with deflector elements 20 which cause the air delivered through casing 12 to converge upon nozzle 18 to form a combustible mixture. The mixture of air and oil is ignited bly an electric spark which jumps between starting electrodes 22 and which is blown forward by the air to ignite the coinbustible air-oil mixture when the burner is operated.

The oil is delivered to the burner assembly from a supply thereof through fuel line 24- and fuel pump and pressure regulating unit 26 and through pipe line 28 to nozzle 18, the regulating unit 26 being preferably arranged to deliver fuel at a maximum operating pressure, ranging between 100 and 130 pounds per square inch.

In operation the oil burner is started in the usual manner by operation of an indoor room thermostat, indicated generally at 16, which closes a circuit to a motor diagrammatically indicated at 30 to operate the air fan 14 and the pressure regulated pump unit 26 and to also open the normally closed solenoid operated inlet valve 32 in the supply line 28.

As illustrated in Fig. l, the oil line 28 is provided with a second normally closed solenoid operated valve 34 and a by-pass line 36 provided with a valve 40 that is manually adjustable to regulate the rate of flow (and hence the pressure) of oil around the valve 34.

As herein shown, an outside thermostat 38 is connected in circuit in series with the normally closed solenoid valve 34 in the pipe line 28 in a manner such that when the outside temperature goes down to a predetermined setting the thermostat 38 actuates solenoid valve 34 to open the same, and the fuel oil is permitted to pass through valve 34 and valve 32 in line 28 to nozzle 18 at a maximum pressure, causing the burner to fire at a high rate. Whenever the outside temperature rises to a predetermined setting thermostat 38 permits solenoid valve 34 to close, and the oil will be caused to flow through by-pass line 36 and regulating valve 40 which reduces the oil pressure to provide a low fire.

In accordance with the present invention, for the purpose of efiicient operation it is preferable in warm weather to operate the burner at a low firing rate and in cold weather at a high firing rate, this result being accomplished by increasing or decreasing the fuel pressure. As also illustrated in Fig. 1, provision is made for simultaneously proportionately increasing or decreasing the amount of air delivered to the burner nozzle for atomizing the fuel.

As illustrated in Fig. 1, an air damper 44 pivotally mounted at 46 adjacent the air intake of the fan may be automatically adjusted in response to the outside temperature to open the damper a small amount when a low fire is called for and a relatively larger amount when a high fire is called for. Damper 44 is fast on the pivot 46 which is provided with an arm 48 connected by a link 50 to the armature of a solenoid 52 connected in circuit in series with the outside thermostat 38. The solenoid 52 is arranged to normally maintain damper 44 in a partially closed position, and when the solenoid 52 is energized by the outside thermostat 38 the damper 44 is further opened to provide an increase in the amount of air to the nozzle 18 corresponding to the increased firing rate for a high fire. Thus, the damper 44 is opened simultaneously with the opening of the valve 34 to provide a high fire.

In a modified form of the present invention illustrated in Fig. 2 the automatic control may be incorporated in a domestic hot water line and be actuated by the differential pressure created when the hot water tap is turned on. In this embodiment of the invention a differential pressure switch 54 in circuit with the normally closed solenoid valve 34 comprises a contact 56 secured to pressure responsive bellows 58 on by-pass line 60, and a stationary contact 62 secured to a casing 63. By-pass line 60 is attached to domestic hot water line 64 having a restricted throat portion 65 intermediate the by-pass connections as shown. In normal operation when hot water tap 66 is closed, contacts 56, 62 are open, and solenoid valve 34 in fuel oil line 28 is normally closed which causes the oil to flow through by-pass line 36 and manually adjustable pressure regulating valve 40 wherein the oil pressure is reduced to provide a low fire.

Whenever tap 66 is opened and a supply of hot water is withdrawn from the hot water system the differential pressure thereby created within line 64 on either side of the restricted opening 65 actuates movable bellows 58, causing switch contact 56 to move toward fixed contact 62, closing the circuit to solenoid valve 34, causing said valve to open and permitting the fuel oil to flow directly through line 28 to nozzle 18 at a maximum pressure, the burner consequently being fired at a high rate.

After the tap 66 is closed the difierential pressure switch contacts are opened by the movement of bellows 58 responsive to the pressure in line 64, and solenoid valve 34 is permitted to again assume its normally closed position, causing'the oil to flow through by-pass 36 and regulating valve 40, thereby again reducing the oil pressure at nozzle 18 and the burner is fired at a low rate.

As herein illustrated, the diflerential pressure switch is also connected in the circuit to the air damper to admit a relatively small amount of air when the burner is operated at a low firing rate and to admit a relatively larger amount of air when the burner is operated at a high firing rate.

Referring now to Fig. 3 illustrating a further modified form of the present invention, represents an oil burner assembly which may and preferably will comprise the oil burner assembly shown in Fig. 1, except as to details hereinafter pointed out, similar numerals identifying corresponding parts.

In the modified form of the invention shown in Fig. 3 in order to regulate the fuel pressure delivered to burner nozzle 18, a bi-pass line 70 is connected between the inlet and outlet lines 24, 28 to the fuel pump 26, as shown, the by-pass line being provided with a manually operated pressure regulating valve 72 and a normally open solenoid valve 74, as shown. Normally open solenoid valve 74 is connected in a circuit to outside thermostat 38 and is arranged to be closed by said thermostat in response to a drop in the outside temperature and permitted to open 41 when said temperature rises above a predetermined number of degrees.

In operation when solenoid valve 74 is open some of the fuel oil is permitted to recirculate through by-pass line 70 to the intake side of the fuel pump and pressure regulating unit 26. Thus, the fuel pressure at nozzle 18 is reduced to a predetermined minimum pressure, and the burner fires at a relatively low rate. Conversely, when the solenoid valve 74 is closed the fuel oil is permitted to pass directly to the nozzle at a predetermined maximum pressure to provide a high fire.

The modified embodiment of the invention shown in Fig. 3 is also provided with a damper 44 operatively connected to solenoid 52 and controlled by outside thermostat 38 to regulate the amount of air intake in accordance with the variations in oil pressures, as above described.

In a modified form of the present invention illustrated in Fig. 4 the automatic controls shown in Fig. 3 may be incorporated in a domestic hot water system. In this embodiment of the invention a by-pass line 88 is connected into hot water line 82 in a manner similar to that shown in Fig. 2, the ends of the line being secured to the line 82 on either side of restricted throat 84 in the water line. A pressure responsive bellows 36 of any usual or preferred type is connected into by-pass line 80, as shown. The differential pressure responsive bellows is arranged to operate a switch, indicated in general at 87 which includes a fixed contact 88 and contact 90 secured to bellows 86 and movable therewith in response to the differential in pressure within hot water line 82. The switch 87 is connected in the circuit to normally open solenoid valve 74 in fuel by-pass line 70, as shown.

In operation when hot water tap 92 is turned on and hot water withdrawn from the system the pressure differential created within water line 82 causes bellows 86 to move contact 90 into contact with contact 38, thus energizing the circuit to normally open solenoid valve 74, causing the same to close, and the fuel is permitted to flow at a maximum pressure directly to the burner nozzle, causing the burner to fire at a high rate, thus rapidly heating the water in the hot water system. Conversely, when the hot water tap 92 is shut off, thus equalizing the pressure on both sides of the restricted throat 84, the solenoid operated valve 74 is permitted to open to 1 permit a portion of the oil to pass through a pressure regulating valve 72 and be recirculated through a bypass line 70 to the intake side of the fuel pump and pressure regulating unit 26.

The embodiment of the invention illustrated in Fig. 4 also contemplates the inclusion of the damper control in circuit with the differential pressure switch, as illustrated, whereby to admit a relatively small amount of air when the burner is operated at a low firing rate and to admit a larger amount of air when the burner is operated at a high firing rate.

It will be understood that in practice the maximum fuel pressure may be adjustably controlled by the fuel pump and pressure regulating unit to provide a high fire pressure of over pounds per square inch and up to pounds per square inch, and that the minimum fuel pressure may be adjustably controlled by the manually adjustable pressure regulators in the by-pass lines to pro vide a low fire pressure below pounds per square inch and down to 70 pounds per square inch for most efiicient operation.

Thus, it may be seen that the present control mechanism automatically adjusts the firing rate of the oil burner according to the heating requirements and preferably in response to variations in outside temperatures and variations in domestic hot water requirements.

Having thus described the invention, what is claimed In a heating system, in combination, an oil burner having an atomizing nozzle and an air supply adjustment means to form a combustible mixture; a fan for supplying combustion air; an oil pump and pressure-regulating unit havinga feed line connected with said nozzle for supplying oil to said nozzle at a selected high pressure sufficient to provide a high fire; an electric motor for driving said fan and oil pump; a first solenoid-operated valve connected in said feed line controlling the flow of oil to said nozzle; a room thermostat connected in circuit with said motor and said first solenoid-operated valve to control the operation of the same; a second solenoidoperated valve connected in said feed line between said pump and said first solenoid-operated valve allowing oil flow to said nozzle at a rate and pressure sufiicient to provide said high fire when said first solenoid-operated valve is open; means for reducing the pressure and rate of oil flow to said nozzle to provide a low fire, including a =by-pass line connected around said second solenoidoperated valve, an oil flow rate adjustment means connected in said by-pass line limiting oil flow to said nozzle at a rate and a selected pressure less than that permitted by said second solenoid-operated valve to provide a low fire, and an outdoor thermostat connected in series with said second solenoid-operated valve in a circuit'independent of the circuit containing said room thermostat for causing said second solenoid-operated valve to close to by-pass the oil through said oil flow rate adjustment means when a low fire is required, said outdoor thermostat controlling said second solenoid-operated valve to permit oil to pass therethrough when a high fire is required; and a solenoid connected in circuit in series with said outdoor thermostat and said second solenoid-operated valve and operatively connected with said air supply adjustment means for simultaneously regulating the supply of air to said nozzle to correspond to changes in the rate of oil supplied to said nozzle to provide a relatively small amount of air for a low fire and a larger amount of air for a high fire.

References Cited in the file of this patent UNITED STATES PATENTS 1,786,901 Doherty Dec. 30, 1930 1,932,269 Harrington Oct. 24, 1933 2,076,768 Denison Apr. 13, 1937 2,115,665 De Florez Apr. 26, 1938 2,319,708 Smith et al May 18, 1943 2,353,498 Perry July 11, 1944 2,362,045 Bliss Nov. 7, 1944 2,397,987 Senninger Apr. 9, 1946 2,516,062 Logan July 18, 1950 2,583,814 Burklin -2 Jan. 29, 1952 

